Self-adjusting pipe clamp and coupling

ABSTRACT

A segmented coupling for use in sealing adjacent pipe ends includes coupling segments having bolting pads at their ends, the ends of the coupling segments including inclined end faces for cooperation with correspondingly inclined end faces of an adjacent coupling segment to produce self-adjustment of the coupling and rigid clamping of the pipe ends upon tightening down of the coupling.

FIELD OF THE INVENTION

This invention relates to a self-adjusting segmented coupling used toconnect and seal the adjacent ends of a pair of pipes, or, to join andseal a nipple of a fitting to a pipe end (hereinafter referred to as apair of pipes). The coupling provides a substantially rigid clamp forthe pipe ends to eliminate or significantly resist relativetranslational or rotational movement of the pipes after assembly of thecoupling, despite differences in the diameter of the pipes or variationsin the diameter of the cylindrical key receiving portion or in thedimensions of the coupling arising in the manufacture thereof.

BACKGROUND OF THE INVENTION

The use of segmented mechanical couplings for joining and sealing theends of pipes has attained wide commercial acceptance, and thesecouplings are now employed in many industries. A typical segmentedcoupling is disclosed in U.S. Pat. No. 3,054,629, to Piatek, issuedSept. 18, 1962. The coupling includes a pair of arcuate couplingsegments which span and embrace the adjacent ends of a pair of pipes,and which compress a sealing gasket into engagement with the externalperiphery at the end of pipes, (hereinafter referred to as the pipeends). The coupling segments have keys on their inner periphery forengagement within grooves in the adjacent pipe ends, and having radiallyextending pads at their ends which receive bolts employed for tighteningdown the coupling. The keys alternatively may be engaged with externalbeads rolled in the pipe ends.

Optimally, when the segments are secured together, they extend in acontinuous ring about the circumference of the pipe ends andsubstantially immobilize the pipe ends and eliminate all gaps betweenthe segments. However, differences in the diameter of stock pipe of thesame nominal diameter result in a less than optimal immobilization ofthe pipe ends, or gaps which permit extrusion of the contained gasket.Similar problems arise due to differences in the depth of the groove onthe pipe ends. If the pipes are undersized in diameter, or the groovediameter is too small then, the bolting pads may be brought into faceengagement with each other, but, the desired immobilizing clamping forceon the pipe ends may not be obtained. If the pipes are oversized indiameter, or the groove diameter is too large, then the bolting pads maynot be brought into face engagement with each other and may leave a gapbetween the bolting pads through which the gasket can extrude. Toovercome these problems, relatively closely spaced apart supports orhangers have been employed to eliminate undesirable flexure at thejoint, or extrusion shields have been provided to support the gaskets inthe area of the gap between the bolting pads.

At least one approach to solving the first problem, that is, flexure atthe joint, is addressed in Gibb et. al., U.S. patent application Ser.No. 358,361, filed Mar. 15, 1982, now Pat. No. 4,471,979, as applied tothin-walled piping which is inherently capable of moving out-of-roundunder compressive stresses produced by the tightening down of thecoupling. Gibb et. al. teach the deliberate formation of the couplingsegments for them to subtend an angle of less than 180 degress at theirend faces, to permit the centers of curvature of the respective couplingsegments to move beyond and to opposite sides of the diametral plane ofthe coupling. This selective deformation of the pipe ends by thecoupling provides for rigid clamping of the coupling onto the pipe endswithout regard to whether the pipes are oversized or undersized withinthe range of manufacturing tolerances. This construction, however, is oflittle utility for use with conventional pipe that is not readilydeformable by a coupling, and does not eliminate the need for extrusionshields in those instances where the bolting pads do not reach faceengagement with each.

U.S. Pat. No. 2,752,173, to Kroos, teaches flexure of the couplingsegments to move the ends thereof in a radially inward direction forthem to clamp onto pipes of less than maximum diameter within the rangeof manufacturing tolerances. While this will produce clamping in thediametral plane of the end faces, flexure of the coupling segments inKroos will produce an increase in the effective length of the innerperiphery of the coupling and preclude clamping of the coupling onto thepipes other than at the ends of the coupling segments. Further, inKroos, flexure of the coupling segments results in movement of the endfaces away from each other and increases the possibility of gasketextrusion.

THE INVENTIVE CONCEPT

The coupling of present invention overcomes these problems and providesa coupling which, optimally eliminates or significantly reduces any gapat the end faces of the coupling segments throughout a range ofmanufacturing tolerances of the pipes or of the grooves, or in thecouplings, and which provides automatic adjustment of the effectivelength of the inner periphery of the coupling to that of the peripheryof any pipe or groove having an external diameter falling within therange; and which automatically provides for self-adjustment of thecoupling to bring the keys into clamping engagement with the pipes orthe bottom walls of the grooves.

These advantages are provided by forming the juxtaposed end faces on atleast one pair of adjacent coupling segments at an oblique angle to thediametral plane of the coupling, hereinafter defined as the diametralX-Z plane, the end faces sliding relative to each other as the couplingis tightened down for them to reduce the effective circumferentiallength of the inner periphery of the coupling, and thus permit thecoupling to clamp onto and secure a pipe having an external diameter orgroove diameters within a given range.

Preferably, the end faces of the couplings are positioned in at leastclosely proximal relationship to each other upon initial assembly of thecoupling onto a pipe having an external diameter or groove diameterwhich is a maximum within a range of manufacturing tolerances. Byarranging for the end faces to be in closely proximal relationship toeach other, the possibility of gasket extrusion is even further reduced,even in the event that the coupling is applied to a pipe having anexternal diameter or groove so severely oversized that the end facescannot meet in face engagement. In such event, an immobilizing clampingforce will be applied to the pipes as the coupling is assembled, and theeffective width of the gap between the end faces will be materiallyreduced. The angular relationship of the end faces modifies the shape ofthe gap to one which more readily resists extrusion of the gasket.

Various orientations of end faces are possible. For example, the endfaces can either be parallel to the diametral axis of the coupling, orparallel to the pipe axis, or in any plane intermediate those planesother than being parallel to the diametral plane of the coupling.

In those embodiments where the end faces are parallel to the pipe axisthe juxtaposed end faces of the coupling segments may be generallyangled in the opposite or in the same directions.

In embodiments which include the opposite angling of the end faces ofone of the coupling segments and complementary angled end faces at theends of the other coupling segment, then the respective pairs of endfaces will act to urge the end of one of the coupling segments inwardlyto decrease the radius of that coupling segment, while simultaneouslyurging the ends of the other coupling segment outwardly to increase theradius of that coupling segment. In this manner, the respective couplingsegments flex and permit the respective coupling segment to move intorigid clamping engagement to compensate for an oversizing, or,undersizing.

Where the angling of both end faces of one of the coupling segment is inthe same direction and the angling of the other coupling segment iscomplementarily positioned then, lateral displacement of the couplingsegments will occur in addition to the flexure of the coupling segments,thus, further assisting the rigid clamping of the coupling onto the pipeends.

In those embodiments where the end faces of the coupling segments areparallel to the diametral axis of the coupling, the juxtaposed end facesmay also be either angled in the same or opposite directions providing acoupling in which movement is permitted between the ends of the couplingsegments in the direction of the axis of the pipes, then, the keys ofthe coupling segments are urged to respectively engage axially oppositeradially extending faces of grooves in the pipe ends or beads on theexterior surface thereof, to further enhance the immobilization of thepipes against relative axial movement.

In these embodiments axial displacement will occur between therespective coupling segments as the coupling is tightened down. Thisreduces the effective internal circumferential length of the innerperiphery of the coupling to bring the coupling into clamping engagementwith the pipes. As the respective coupling segments and their keys movein opposite axial directions, the keys of one coupling segment willengage one side wall of the grooves or beads associated with the pipeends, and the keys of the other coupling segment will engage theopposite side in order to immobilize the respective pipe ends againstrelative axial movement.

By providing a coupling in which the ends of the coupling segments arecapable of radial movement relative to each other during tightening downof the coupling, the present invention provides a self adjustingcoupling which can be brought into clamping engagement with the pipesdespite oversizing or undersizing.

Whether the predominant angular direction is along the diametral planeof the coupling or along the axis of the pipe, the end faces may beother than planar and may be concave, convex, V-shaped, or of othershapes, provided that the shapes of the juxtaposed faces permit movementrelative to each other. By selectively varying the shape of the endfaces and the ability of the coupling segments to flex, variouscombinations are possible which permit adjustable seating of thesegments on the pipe, both circumferentially and axially.

For convenience, the present invention has been described employing boltpads and bolt connectors, to join the coupling segments. However, thebenefits of the invention may be obtained where other means are employedfor securing and tightening the coupling segments, such as hinge andtoggle arrangements, circumferential straps, or the like.

To assure sufficient room for adjustment to pipe diameter when bolts andbolt pads are employed, the pads of the respective coupling segments arepreferably positioned to remain spaced from each other in the finallyassembled condition of the coupling.

Further, the bolt receiving apertures of the bolting pads are preferablydivergent in the axial direction thereof towards the end faces. In thismanner, not only can offsetting or skewing of the coupling segmentsduring tightening down of the coupling be accommodated, but also partialassembly of the coupling can be effected prior to it being assembledonto the pipe ends.

The coupling has been illustrated as a pair of coupling segments forencircling relationship with the pipe ends. It is to be understood thata coupling of multiple coupling segments having combined arcuate lengthssufficient to provide for encircling relationship with the pipe ends mayalso be employed. Further the invention has been illustrated withgrooved end pipe. It will be understood that the improvement in theclamping force which may be achieved in accordance with the teachings ofthe present invention, also has particular applicability for use incouplings designed for joining pain end pipes.

DESCRIPTION OF THE ACCOMPANYING DRAWINGS

The invention will now be described with reference to the accompanyingdrawings, which are illustrative of embodiments of the invention fallingwithin the scope of the appended claims, and in which:

FIG. 1 is a front elevation of one form of pipe coupling of the presentinvention, showing the interrelationship of the coupling segments, aportion of the coupling segments having been shown in section forclarity of illustration;

FIG. 2 is a top plan view of the lowermost coupling segment shown inFIG. 1;

FIG. 3 is a front elevation of another form of pipe coupling of thepresent invention, a portion of the coupling segments being shown insection for clarity of illustration;

FIG. 4 is a top plan view of the lowermost coupling segment of FIG. 3;

FIG. 5 is a fragmentary perspective view of a bolting pad in accordancewith FIGS. 1 through 4;

FIGS. 6, 7 and 8 illustrate modifications of the form and shape of theinter-engaging end faces of the bolting pad of FIG. 5;

FIG. 9 is a front elevation of another form of coupling segment of thepresent invention, to be used in a combination with an identicalcoupling segment to provide a pipe coupling;

FIGS. 10 and 11 are side elevations of a coupling assembled from a pairof coupling segments as shown in FIG. 9, FIG. 10 illustrating thecoupling prior to tightening down of the bolts, and FIG. 11 illustratingthe coupling subsequent to the tightening down of the bolts and theconsequential movement between the respective coupling segments;

FIG. 12 is a front elevation of two coupling segments of anotherembodiment of pipe coupling of the present invention in a position readyfor assembly to each other;

FIGS. 13 and 14 are respectively a top plan view and an underside planview of the bolting pad illustrated in a cross-section in FIG. 12;

FIG. 15 is a fragmentary perspective view of one of the bolting pads ofFIGS. 12 through 14;

FIG. 16 is a side elevation of FIG. 12 showing the coupling segmentsassembled to each other and illustrating the permitted slippage betweenthe coupling segments;

FIG. 17 is a section taken on the line 17--17 of FIG. 12, andillustrating the movement between the diametrically opposite pair ofbolting faces;

FIG. 18 is a fragmentary perspective view of the bolting pads of FIGS.12 through 17;

FIG. 19 is a front elevation of two coupling segments of still anotherembodiment of the coupling of the present invention in position forassembly to each other;

FIG. 20 is a fragmentary perspective view of the bolting pads of FIG.19;

FIG. 21 is a sectional side elevation of the coupling illustrating amodification in the orientation of the track bolts and bolting pads;

FIG. 22 illustrates a hinge incorporating the inclined end faces of thepresent invention;

FIG. 23 is a perspective view of FIG. 22;

FIG. 24 illustrates the hinge of FIG. 22 when in an opened position;

FIG. 25 is an exploded prespective view of the hinge members of FIGS. 22through 24; and,

FIG. 26 is a fragmentary perspective view of a coupling, showing analternative form of traction mechanism to be employed in substitutionfor the track bolts of the preceding figures.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

Referring now to FIGS. 1 and 2, the coupling, as is conventional, isillustrated as comprised of two identical coupling segments, 10 and 12,having outwardly extending bolting pads 14 and 16 which are suitablyapertured to receive track bolts 18. The bolts 18 extend through therespective pairs of the bolting pads, and carry nuts 20 which areemployed for the tightening down of the coupling.

The coupling segments 10 and 12 are provided with an internal gasketreceiving channel 22, (the gasket being omitted for the sake ofclarity). The gasket, as is well known in the art, may either be acontinuous gasket which is slipped over the ends of the pipes andbrought into a bridging relationship therewith, or, it may be a splitgasket which is wrapped around the pipes in a bridging relationship withthe ends thereof, or, the gasket may be comprised by gasket segments.Preferably, in those instances in which a split gasket or gasketsegments are employed, the radial end faces thereof are located at aposition spaced circumferentially from the faces of the bolting pads. Ininstances in which gasket segments are employed, preferably they aresecured to the associated coupling segments, for example, by anadhesive.

On each side of the gasket receiving channel of 22, the couplingsegments are formed with radially inwardly extending keys 24, which arereceived in grooves (not shown) in the pipe ends. Alternatively, (notshown) the keys may be engaged behind radially outwardly extending beadsor other projections formed on or secured to the exterior periphery ofthe pipe ends.

The coupling segment 10 terminates at its ends in inclined end faces 26,and, the coupling segment 12 terminates in inclined end faces 28.

In the following description, and in the appended claims, theorientations of the end faces of the couplings and the directions inwhich they are inclined are defined by reference to the respective axesand planes of coupling, which are summarized as follow:

the X axis is an axis related to the end faces of the coupling segments,and is an axis extending through the line of generation of the radii ofthe respective coupling segments. Within minor variations, the X axisincludes and passes through the center of the assembled coupling, orprovides a bisector of a line extending between the lines of generationof the radii of the respective coupling segments. For convenience ofillustration, the X axis has been illustrated in a horizontalorientation. It will, however, be appreciated that the X axis may be inany orientation in actual use of the coupling;

the Y axis is an axis extending through the line of generation of theradii of the respective coupling segments, and which is perpendicular tothe X axis;

the X-Y plane is a plane including both the X axis and the Y axis, andwhich thus is perpendicular to the pipe axis;

the Z axis generally corresponds to the pipe axis, and is thelongitudinal axis of the coupling which extends through the point ofintersection of the X axis and the Y axis, the Z axis thus extendingperpendicular to the X-Y plane;

the X-Z plane is a diametral plane which includes both the X axis andthe Z axis;

the Y-Z plane extends perpendicular to the X-Z plane and includes boththe Y axis and the Z axis.

These axes are illustrated in FIGS. 1 and 2 of the drawings, and inothers of the drawings to provide visual reference to those axes and thepositioning of the respective X-Y, Y-Z and Z-X planes.

In FIGS. 1 and 2, the respective pairs of end faces each extend parallelto the Z axis and are each inclined at opposite oblique angles withrespect to the horizontal diametral X-Z plane extending through thecoupling, the end faces 26 defining male members extending from the endsof the coupling segment 10, and the end faces 28 defining female membersextending inwardly of the coupling segment 12.

The bolting pads 14, 16 of the respective coupling segments 10 and 12are provided with reinforcing flanges or buttresses 30, which transferthe cantilever loading exerted on the bolting pads 14, 16 by the trackbolts 18 directly to the ends of the coupling segments 10 and 12.

While various angles are suitable, the end faces 26 and 28 of FIGS. 1and 2 are arranged at an angle of approximately 60 degrees to thehorizontal diametral X-Z plane, and preferably at a slight includedangle to each other, for example, in the order of 6 degrees, in orderthat the end faces diverge from each other in a radially outwarddirection. Further, the bolting pads 14, 16 may be positioned at aslight included angle of about 3 degrees to the horizontal diametralplane X-Z for them to assist in sliding the end faces 26, 28 relative toeach other, and the progressive closing of any gap existing between theend faces.

Upon initial positioning of the segments, a minor gap will be presentbetween the end faces 26 and 28 at positions radially outwardly of theline of inter-engagement of the faces. The existing gap will narrow asthe coupling is tightened down until the respective end faces 26 and 28are substantially in face engagement with each other. The tighteningdown of the bolts 18 will cause the end faces 26 and 28 to sliderelative to each other, the end faces 26 sliding downwardly relative tothe end faces 28, and, the end faces 28 sliding upwardly relative to theend faces 26.

As a result, the end faces 26 act to force the respective end faces 28radially outwardly with a wedging action to flex the coupling segment 12and increase the effective radius thereof. Simultaneously, therespective end faces 28 act to force the end faces 26 radially inwardlyto decrease the effective radius of the coupling segment 10.

The coupling segment 10 is thereby drawn downwardly into clampingengagement with the pipes (not shown), while simultaneously the ends ofthe coupling segment 10 are forced radially inwardly into clampingengagement with the pipes. The coupling segment 12 is drawn upwardlyinto clamping engagement with the pipes, and, the respective pairs offaces are moved into parallelism with each other for them to imprisonthe gasket and prevent extrusion thereof.

Due to the radially outward movement of the ends of the coupling segment12, the end faces 28 of the coupling segment 12 progressively move intoparallelism and face contact with the end faces 26, ultimately resultingin the closure or the near complete closure of the gap between therespective pairs of end faces 26 and 28.

The respective sliding actions and the flexure of the coupling segmentsaccompanied by the closure of the gap between the bolting faces 26, 28,will in turn produce movement of the bolting pads 14, 16 towardsparallelism with each other and produce full seating of the heads of thetrack bolts 18 and the nuts 20.

As will be appreciated, each of these movements occurs concurrently andin combination upon the tightening down of the coupling. While thecombined movements may possibly reposition those portions of the endfaces 26 and 28 which bridge the gasket receiving channel 22 out ofcircumferential alignment with each other, there are no adverseconsequences and in the fully tightened down position of the couplingthe bridging portions remain overlapped in the radial direction.

By the provision of the reinforcing flanges or buttresses 30 proximatethe bolting pads 14, and 16 and the orientation of the supplementalbuttresses 14a, 16a for them to extend substantially tangentiallybetween the body of the coupling segments 10 and 12 and the respectivebolting pads 14 and 16, flexure of the respective coupling segments 10and 12 at the ends thereof is minimized, and is limited dominantly tothe central arcuate portion of the coupling segments.

As the respective end faces 26 and 28 are free to slide relatively toeach other with the coupling segments 10 and 12 capable of movingtowards to each other in the direction of the vertical Y axis, theeffective circumferential length of the inner periphery of the couplingcan be decreased as required in order for the keys 24 of both of thecoupling segments 10 and 12 to move into substantially continuousclamping line engagement with the pipe periphery, or, with the bottom ofthe grooves in the pipe ends. The respective coupling segments will movethrough a position in which their inner peripheries lie on a circle, toa position in which the respective coupling segments 10 and 12 defineintersecting arcs. While this may result in a slight distortion of thepipe ends from a condition in which they are truly round, it also actsto improve the rigidity of inter connection and support of the pipes.

Referring now to FIGS. 3 and 4, the same reference numerals are used asthose used in FIGS. 1 and 2 to indicate those members which are incommon with FIGS. 1 and 2. In FIGS. 3 and 4, the bolting pads 14, 16 atone side (the left) of the coupling have been interchanged and thus theangle of the associated end faces 28 and 26, identified in FIG. 3 as 26aand 28a, has been reversed. The respective coupling segments 10 and 12are otherwise closely similar in all respects with the coupling segments10 and 12 of FIGS. 1 and 2.

By repositioning the bolting pads 14 and 16, and thus repositioning theend faces 26a and 28a as shown in FIGS. 3 and 4, an increase in thepermissable extent of the movement of the coupling segments 10 and 12towards each other is obtained, accompanied by a lateral shifting inopposite directions of the respective coupling segments 10 and 12 indirections substantially parallel to the horizontal X axis.

In this embodiment, tightening down of the track bolts 18 will initiallyresult in a leftward movement of the coupling segment 10, and acorresponding rightward movement of the coupling segment 12. This willbring the male projection defining the end face 26 at the righthand sideof the coupling member 10 into clamping engagement with the exterior ofthe pipes, at which point it will be substantially immobilized, andsimilarly, will bring the male projection defining the end face 26a atthe lefthand side of the coupling segment 12 into clamping engagementwith the exterior of the pipes, at which point it similarly will becomesubstantially immobilized.

On the continuance of the tightening down of the bolts 18, therespective bolting pads 14, 16 will move towards parallelism to flex therespective coupling segments, and the respective end faces 28 and 28awill slide up the immobilized end faces 26 and 26a, and bring therespective pairs of end faces 26, 28 and 26a, 28a into parallelism andface engagement. At the same time the effective circumferential lengthof the inner periphery of the coupling is decreased to bring the keys 24of the respective coupling segments into clamping engagement with theperipheries of the pipe ends or the bottoms of the grooves therein.

By decreasing the effective circumferential length of the innerperiphery of the coupling, accompanied by some possible flexure andovalling of the pipe end, clamping engagement is obtained throughoutsubstantially the entire periphery of the pipe end, while at the sametime, the respective end faces move into parallelism and face engagementwith each other to obviate the possible extrusion of the containedgasket when under pressure loading.

Referring now to FIG. 5, the ends of the coupling segments illustratedat the left hand side of FIG. 3 are shown in exploded perspective view.In FIG. 5, the respective end faces 26a, 28a extend parallel to the Zaxis, and are arranged at an oblique angle to the X-Z plane. As thecoupling is tightened down, the end face 28a will progressively movedown the end face 26a, with the bridging portions of the end faces 26aand 28a moving into face engagement with each other to confine andimprison a gasket (not shown) located within the coupling segments 10and 12.

In the embodiments of FIGS. 1 through 5, the engagement of the keys 24within the grooves of the pipe ends is utilized to align the respectivecoupling segments. If axial misalignment or offsetting of the boltingpads occurs, then, there is a possibility of distortion of the containedgasket at the plane of contact between the end faces, with possiblelifting of the edges of the sealing gasket from their face contact withthe outer periphery of the pipe ends.

To eliminate this possibility, the respective end faces can be formed asillustrated in FIGS. 6 and 7. In FIG. 6, the end face 28a is formed forit to be convex, and, the end face 26a is formed for it to be concave.This results in the respective end faces being in the form of surfacesof a cylindrical section having its axis extending in the diametral X-Yplane and at an oblique angle to the X axis and, produces a centeringaction upon initial assembly of the respective coupling segments to eachother. As the respective surfaces are sections of a cylinder, therespective end faces are free to move relative to each other in the X-Yplane, but are restrained or precluded from moving laterally in thedirection of the Z axis and becoming offset relative to each other.

While in FIGS. 5 and 6 the end faces have been shown as being formed,respectively, as a line parallel to the Z axis and a curve having itscenter lying in the X-Y plane, the respective profiles being translatedalong a line oblique to the X axis, it will be appreciated that the endfaces 26 and 28 may take other forms. Instead of being formed by astraight or a curved profile translated along an axis oblique to the Xaxis and lying in the X-Y plane, the profile could be translated along acurved line lying in the X-Y plane, as illustrated diagrammatically inFIG. 6. Also, instead of being comprised of a straight line or curve,the profile could be comprised of a combination of straight lines,curves, or straight lines and curves, to provide end faces that are ofsaw tooth, wave form, castellated, crenellated, or formed of dihedrals.Such a non-linear profile greatly reduces the possibility of sabotageattempts on the contained gasket by forcing a knife blade or other sharpinstrument between the end faces and cutting or puncturing the gasket.

FIG. 7 illustrates one such embodiment, in which the respective endfaces 26a and 28a are formed as dihedrals which converge downwardlytowards each other in V-shape. Such a V-shape arrangement of the endfaces again retrains or precludes lateral movement or offsetting of theend faces, while at the same time permitting sliding movement of the endfaces relative to each other in the direction of the X-Y plane of thecoupling.

Referring to FIG. 8, there is shown a modification of the bolting pads14, 16 of FIGS. 5, 6 and 7. In FIG. 8, the end face 26a is replaced by atongue 26b which extends beyond the end of the coupling segment 12, andwhich is flanked by inclined end face portions 26c. The coupling segment10 is configured for it to be of a complementary form, such that thetongue 26b inter-fits and is received between the buttresses 30 of thebolting pad 16, and fills a recess formed in the bolting pad 16 toprovide a continuation of the axial wall of the gasket-containingchannel 22. The end of tongue 26b is shown as extending parallel to theZ axis and is axially straight. The end of the tongue 26b could be ofother configurations, such as saw-tooth, wave-form, castellated orcrenellated, again for the purpose of minimizing the possibility ofsabotage attempts on the contained gasket.

Referring now to FIG. 9, there is shown a coupling segment 40 which isto be assembled with an identical coupling segment to provide a splitcoupling. In this embodiment, axial movement or offsetting of therespective bolting pads in the direction of the Z axis is intentionallypermitted in order to obtain a reduction in the effectivecircumferential length of the inner periphery of the coupling, and topermit the coupling to clamp onto and secure pipes having an externaldiameter within a range of tolerances of such pipes.

In FIG. 9, the coupling segment 40 is provided with bolting pads 42 atits respective ends, the respective bolting pads including reinforcingflanges or buttresses 44 for the purpose of controlling flexing andbending of the bolting pads. The end faces 46 of the coupling segmentare co-planar with each other, and extend at an oblique angle ofapproximately 30 degrees to the diametral X-Z plane of the coupling andperpendicular to the Y-Z plane.

As is illustrated in FIG. 10, upon assembly of the coupling from two ofthe coupling segments 40 of FIG. 9, and using track bolts 48 and nuts 50in manner previously described, the end faces 46 are brought intoproximity or into face engagement with each other with the respectivecoupling segments 40 enclosing and imprisoning the gasket [not shown].In the event that the pipe ends are of diameter falling within the rangeof tolerances, the respective bolting faces 46 will engage each other inparallelism and in face engagement, and the possibility of extrusion ofthe gasket at the bolting faces is precluded. The coupling segments 40in FIG. 10 are shown in the position they would occupy when the twocoupling segments are aligned with each other and are not offset.

If the pipe ends are of less diameter than shown in FIG. 10 then, and asshown in FIG. 11, upon tightening down of the coupling the respectivecoupling segments will slide laterally of each other to an offsetposition until such time as the keys 42 of respective coupling segmentsbottom down and clamp onto the respective pipes. This offsetting of thecoupling segments is permitted by the elongation of the bolt hole 52through which the threaded shank of the track bolt 48 extends.

By permitting lateral movement of the respective coupling segments,provision is made for the reduction of the effective internalcircumferential length of the inner periphery of the coupling, and, theclamping of the pipes by the coupling in the event that the pipes areundersized. Should the pipes be oversized as opposed to beingundersized, then, the respective coupling segments will be slid in theopposite direction to that shown in FIG. 11. Such sliding movement willresult in an increase in the effective internal circumferential lengthof the inner periphery of the coupling, enabling it to accommodate andclamp onto the larger pipes.

As illustrated in chain-dotted lines in FIG. 10, there is possibilitythat the end faces will not come into contact with each other in one ora combination of antagonistic circumstances. In the event that thecoupling is applied to a pipe having an out-of-round end, or one inwhich the grooves have been formed of insufficient depth to accomodatethe required extent of inward movement of the keys 42, or, in the casethat the coupling segments are undersized, or, any combination of suchcircumstances, then, there is a possibility that the end faces willremain spaced from each other.

The first possibility would be overcome by the pipe end moving intoround as the coupling is tightened down. The other two possibilitieswould not, however, be overcome and a gap as shown at A in FIG. 10 wouldbe present between the end faces of the coupling segments in the fullytightened down condition of the coupling. Such a gap is to be avoided,in that it could possibly permit gasket extrusion and require the use ofan extrusion shield. This possibility of gasket extrusion even in thepresence of a gap is, however, significantly minimized by orienting theend faces in an inclined position relative to the X-Z plane of thecoupling. In this orientation, the width of the gap A in a directionperpendicular to the end faces 46 is substantially less than the widthof the gap when measured in the X-Y plane of the coupling as indicatedat B in FIG. 10. The gap B represents the spacing of the end faces ofthe bolting pads as it would appear in a coupling having end faces thatextend parallel to the X-Z plane. As the probability of gasket extrusionis reduced in relationship to a reduction in the width of the gap B, andas the gap A is of lesser width than the gap B, the possibility ofgasket extrusion in the antagonistic circumstances mentioned above issignificantly reduced, thus reducing or eliminating the necessity toemploy extrusion shields.

As the bolting faces 46 act to force offsetting of the respectivecoupling segments in the direction of the Z axis, the possibility existsof moving the keys 42 of one of the coupling segments into engagementwith one of the radial walls of the grooves in the pipe ends, while atthe same time moving the keys 42 of the other coupling segment intoengagement with the opposite radial wall of the grooves in the pipeends, thus further immobilizing the pipes against relative movement.

In FIGS. 9 through 11, the end faces are co-planar for them to producebodily movement or offsetting of the respective coupling segments indirections axially of the pipe ends without skewing of the couplingsegments. FIGS. 12 through 18 illustrate another embodiment of couplingin which the advantage of offsetting of the coupling members isprovided, as in the embodiment of FIGS. 9 through 11, and additionallyprovision is intentionally made for rotation of the respective couplingsegments in opposite directions about the Y axis. In FIG. 12, therespective coupling segments 54 are provided with bolting pads 56,which, as previously described are provided with buttresses 58. Therespective bolting pads have end faces 60 which extend perpendicular tothe Y-Z plane of the coupling, and which are inclined at an angle in theorder of 30 degrees to the diametral X-Z plane of the coupling, but,which are oppositely inclined relative to that plane.

Upon assembly of a coupling from two of the coupling segments 54, and,as more clearly shown in FIGS. 16 and 17, the end faces at one side ofthe coupling will move axially and become offset (FIG. 16), while at thesame time the end faces 60 at the opposite side of the coupling willmove axially in the opposite direction (FIG. 17) and become offset. Inthis manner, the coupling segments are deliberately rotated about the Yaxis for them to be inclined oppositely relative to the X-Y plane of thecoupling, i.e., the plane perpendicular to the longitudinal axis of thepipes. As a consequence, the effective internal circumferential lengthof the inner periphery of the coupling can be increased or decreased asrequired in order to accommodate oversized or undersized pipes while atthe same time skewing the keys 62, such that the ends thereof moveoppositely in directions parallel to Z axis, and move into abutment attheir ends with the respective opposite radial walls of the pipegrooves.

A modification of the bolt receiving apertures in the bolting pads 56 isillustrated in FIGS. 12 through 15, that modification finding equalapplicability in the embodiments of FIGS. 1 through 11, and, theembodiment later described with respect to FIGS. 19 and 20.

In FIGS. 11 through 15, the bolt receiving apertures 64 are formed withaxially extending outwardly diverging portions 64a and 64b, which extendparallel to the Z axis, and which preferably are oriented at an angle of30 degrees to the longitudinal axis 64c of the apertures 64. When atrack bolt is inserted into the aperture 64, instead of being guidedclose to the longitudinal axis of the aperture and held aligned with thelongitudinal axis within relatively close limits, the track bolt canswing within the 30 degrees extent of the flared aperture portions 64aand 64b, to opposite sides of the axis of the apertures, as indicated bythe chain dotted lines in FIG. 14.

The resulting swinging movement facilitates the assembly of therespective coupling segments 54 over the pipe ends and over a gasketpositioned on the pipe ends, ready for the insertion of a bolt throughthe opposite pair of bolting pads, and, the subsequent torquing down ofthe nuts to tighten the coupling. The flaring of the portions 64a and64b in no way affects the correct positioning of the track bolt in itsrequired orientation, lateral shifting of the track bolt relative to thebolting pad 56 being precluded by the correctly dimensioned aperture 64itself.

Referring now to FIGS. 19 and 20 an embodiment of the coupling is shownwhich combines the features of the coupling of FIGS. 3 and 4, and alsothose of the coupling FIGS. 12 through 18.

In FIG. 19, the respective coupling segments 70 are provided withbolting pads 72, the bolting pads having reinforcing buttresses 74, endfaces 76, and keys 78. The end faces 76 are each planar, and, inaddition to being oppositely inclined relative to the Z axis, and alsoare inclined relative to the X axis.

The respective bolting faces 76 each include a central gasket confiningwall 80 providing a gasket receiving channel 82 for confining a gasket.

Upon assembly of the coupling by the use of track bolts as previouslydescribed, in addition to the respective bolting pads being able to moveoppositely in a plane inclined to the X-Z plane and to move laterallyand rotate about the Y axis, as discussed with respect to the embodimentof FIGS. 12 through 18, the respective bolting pads can also moveoppositely in a plane inclined to the X-Z plane and laterally of thelongitudinal X axis of the coupling in the manner discussed with respectto FIGS. 3 and 4 to bring the respective keys into engagement with thegroove walls. Additionally, one of the bolting pads of one of thecoupling segments 70 is urged in the direction of the X axis and intoengagement with the outer surface of the pipe or the bottom wall of thepipe groove, while the other bolting pad acts to urge the juxtaposedbolting pad in an opposite direction of the X axis and into clampingengagement with the pipe end or the bottom wall of the pipe groove. Inthis manner, lateral offsetting of the respective pairs of bolting padsin the direction of the Z axis is accomplished, while at the same timerotation of the respective pairs of bolting pads about the Y axis isprovided, and, in addition, radial offsetting of the respective pairs ofbolting pads relative to the X axis is provided in order to immobilizethe pipes to the greatest possible extent.

Throughout these combined movements of the bolting faces 76, the boltingfaces remain in face contact with each other, and, the central ribs 80inhibit extrusion of the gasket when under compression.

While throughout the description of the preferred embodiments referencehas been made to couplings comprised of two coupling segments, it willbe appreciated that the coupling may be comprised of three or more suchsegments arranged in end-to-end relationship for them collectively toencircle the pipe ends. In such arrangements it may be desirable toinclude stops to preclude over-tightening at any one of the interfaceswhich might otherwise result in a gap at one of the interfaces. Anexample of a stop is shown as 30a in FIG. 1.

In such an embodiment of coupling, the respective end faces of thebolting pads may take any one of the forms described above with respectto the drawings, or, may be a combination of the various different onesof those forms. Optionally, some of the coupling segments could behinged to each other in a conventional manner, the inclined end facesbeing provided on the end-most coupling segments of the assembly.

Instead of being substantially planar, as previous described, thebolting pads of the embodiments of FIGS. 9 through 20 can be so formedthat the track bolts forceably assist in the lateral offsetting of thecoupling segments relative to each other. Such an embodiment isillustrated in FIG. 21, in which the respective coupling segments 100are provided with end faces 102 which are inclined relative to thediametral X-Z plane of the coupling, the bolting pads 104 having bosses106 formed thereon having bolting faces which are inclined to the saiddiametral X-Z plane of the coupling, and which also are inclinedrelative to the end faces 102. In this embodiment, upon insertion andtorquing down of the track bolt 108, resultants of the clamping forcewill act in the plane of the inclined end faces 102 to force relativesliding movement between those faces, and, to force offsetting of therespective coupling segments, and clamping engagement of the couplingsegments with the radial walls of the pipe grooves.

FIGS. 22 through 25 illustrate a modification of the bolting pads of theprevious figures, and which advantageously can be used in the manner ofa hinge, while at the same time retaining the advantages previouslydiscussed with respect to the inclined end faces.

In FIGS. 22 through 25, the respective coupling segments 120, 122 eachdefine a gasket receiving channel 124, and terminate in complementaryinclined end faces 126, 128, as previously described in reference toFIGS. 9 through 18. The adjacent ends of the coupling segments each areformed with lugs 130 having nose portions which extend circumferentiallybeyond the end faces 126, 128, and which extend perpendicular to theplanes of the respective end faces 126 and 128.

The respective lugs 130 are interfitted, and are of lesser width thanthe spacing between the lugs within which they are interfitted, therespective lugs being secured to each other by a bolt 132 extendingthrough aligned bores in the lugs. The head of the bolt 132 reactsagainst an end most lug associated with one of the coupling segments(the coupling segment 122), and a nut 134 threaded onto the bolt 132reacts against an end most lug associated with the other couplingsegment (the coupling segment 120).

The axis of the bolt lies in the plane of the end faces 126, 128, thuspermitting hinging of the coupling segments about the axis of the bolt,and, permitting sliding movement between the respective end faces 126,128. Upon torquing down of the nut 134, the lug 130 associated with thecoupling segment 120 is forced to slide leftwardly, along the bolt,while simultaneously the head of the bolt acts to force the lug 130associated with the coupling segment 122 rightwardly to slide the endfaces 126, 128 in opposite directions relative to each other, and, toreduce to effective internal circumferential length of the innerperiphery of the coupling for the reasons previously described, and inthe manner previously described.

Referring particularly to FIG. 24, such a hinge construction has theadvantage of providing a swing-over connection between the respectivecoupling segments, thus allowing one of the coupling segments to bepositioned over a gasket positioned on the pipe ends, and then the othersegment to be swung laterally over the gasket towards the closedposition of the coupling. The opposite end of the coupling then would beclosed by means of bolting pads as previously described.

Alternatively, both ends of the coupling can be provided withinterfitting inclined lugs having bores arranged with their axes in theplane of the associated end face, and, the coupling closed by anappropriate removable traction mechanism, such as toggle mechanism,reacting against the lugs, and which permits the lugs to be drawn intointerengagement with each other to permit insertion of the bolt 132.FIG. 25 illustrates in chain-dotted lines 130a a suitable configurationof the lugs to permit the use of such a toggle mechanism or othersuitable form of traction mechanism.

While the various embodiments of the invention have been described withreference to the use of track bolts for securing the coupling members toeach other and providing for the required offsetting clamping action, itwill be appreciated that any suitable form of traction mechanism couldbe employed in substitution for track bolts. One such mechanism isillustrated in FIG. 26, in which the coupling segments 110 each areprovided with radially extending traction lugs 112. One of the lugs isan engaged by a pin 114 carrier by a yoke 116 having arms 118 and abridging portion 120. The bridging portion 120 has a threaded bore inwhich a machine bolt 122 is received, the end of the bolt 122 reactingagainst the lug 112 of the other coupling segment. Numerous other formsof traction mechanism could be employed, including an appropriate togglelinkage hinged or otherwise secured to one of the lugs 112 and reactingagainst the other of the lugs.

In the embodiments described above, the gasket has been omitted for thesake of clarity of illustration. A typical gasket 140 and its positionwithin the coupling segments is illustrated in FIG. 17, as is itsrelationship to the pipe ends 142, 144, and, the relationship 62 of thekeys of the coupling segments to the grooves in the pipe ends. As analternative to the gasket 140, O-rings received within grooves in thecoupling segments can be employed. Other sealing means may also beemployed as specific applications require. While a single groove isshown in each of the pipe ends, it will be appreciated that multiplegrooves, either in cylindrical or fir-tree arrangement could be providedin the pipe ends, and, the respective coupling segments be provided withappropriate multiple keys. Further, it will be readily appreciated thatinstead of grooving the pipe ends as illustrated in FIGS. 17, the pipeends could be beaded or have abutment members secured thereto, and, thekeys clamp behind the beads or abutments and directly onto the outerperiphery of the pipes. The pipes also can be plain ended and thecoupling segments clamped directly on to the pipes.

While not illustrates, the end faces of the bolting pads of FIGS. 8through 19 also can be formed in the manner illustrated and describedwith respect to FIGS. 6 and 7 of the drawings. In such case, the endfaces would be formed for them to accommodate the expected directions ofrelative movement between the juxtapopsed ends of the coupling segments,either axially in relation to the Z axis, radially in relation to the Xaxis, or in a combination of those directions in relation to the X-Zplane of the coupling.

By providing for skewing and offsetting of the gasket segments, theutility of the coupling is extended to its use in clamping onto the endsof pipes of different diameter within the range of manufacturingtolerances, namely, one pipe which is oversized, and another pipe whichis undersized with respect to the standard dimension.

It will be appreciated that various other combinations may be made ofthe couplings described with respect to the preferred embodimentswithout departing frm the scope of the appended claims, and, that suchvariations and modifications are to be considered as included within thescope of the appended claims.

What is claimed is:
 1. In a pipe coupling of the type including plural arcuate coupling segments, radially inwardly extending engagement means on each said coupling segment for clamping engagement with ends of pipe members arranged in juxtaposed relationship, radial and axial walls of each said coupling segment providing for the reception of sealing means, and means for securing said coupling members to each other in end-to-end encircling relationship about said pipes, the improvement comprising:juxtaposed end faces on at least one pair of adjacent coupling segments positioned in sliding face engagement with each other, said end faces each being inclined at an oblique angle to the diametral X-Z plane of the coupling and extending perpendicular to the Y-Z plane of the coupling, said end faces being positioned in at least closely proximal relationship to each other upon initial assembly of the coupling onto a pipe having an external diameter which is a maximum diameter within a range of manufacturing tolerances of said pipes; and, traction means operative to urge said end faces towards each other and then to slide said end faces across each other to reduce an effective internal circumferential length of an inner periphery of said coupling, thus permitting said engagement means to clamp onto and secure a pipe having an external diameter falling within said range of manufacturing tolerances.
 2. The pipe coupling of claim 1, in which said juxtaposed end faces are planar.
 3. The pipe coupling of claim 1, in which said juxtaposed end faces inter-fit, and comprise at least one surface formed by translating a profile along a reference line extending parallel to the Y-Z plane and oblique to the X-Z plane.
 4. The pipe coupling of claim 1, in which each end of each said coupling segment is formed with said inclined juxtaposed end faces.
 5. The pipe coupling of claim 4, in which said juxtaposed end faces are inclined in the same direction relative to said X-Z plane.
 6. The pipe coupling of claim 4, in which said juxtaposed end faces are oppositely inclined relative to said X-Z plane.
 7. In a pipe coupling of the type including plural arcuate coupling segments, radially inwardly extending engagement means on each said coupling segment for clamping engagement with ends of pipe members arranged in juxtaposed relationship, radial and axial walls of each said coupling segment providing for the reception of sealing means, and means for securing said coupling segments to each other in end-to-end encircling relationship about said pipes, the improvement comprising:juxtaposed end faces on at least one pair of adjacent coupling segments positioned in sliding face engagement with each other, said end faces each being inclined at an oblique angle to the diametral X-Z plane of the coupling, said end faces each being inclined at an oblique angle to the Z axis, and also being inclined at an oblique angle to the X axis, said end faces being positioned in at least closely proximal relationship to each other upon initial assembly of the coupling onto a pipe having an external diameter which is a maximum diameter within a range of manufacturing tolerances of said pipe; and, traction means operative to urge said end faces towards each other and then to slide said end faces across each other to reduce an effective internal circumferential length of an inner periphery of said coupling, thus to permit said engagement means to clamp onto and secure a pipe having an external diameter falling within said range of manufacturing tolerances.
 8. The pipe coupling of claim 7, in which said juxtaposed end faces are planar.
 9. The pipe coupling of claim 7, in which said juxtaposed end faces inter-fit and comprise at least one surface formed by translating a profile along a reference line extending oblique to said X, Y and Z axis.
 10. The pipe coupling of claim 7, in which each end of each said coupling segment is formed with said inclined juxtaposed end faces.
 11. The pipe coupling of claim 10, in which said juxtaposed end faces are inclined in the same direction relative to said X-Z plane.
 12. The pipe coupling of claim 10, in which said juxtaposed end faces are oppositely inclined relative to said X-Z plane.
 13. The pipe coupling of claim 1, in which said securing means include abutment members on adjacent coupling segments, and a traction member interconnecting said abutment members for closing said coupling, said traction member being comprised by a yoke having spaced parallel links interconnected by a transverse pin at one of their ends and interconnected by a bridge at the other of their ends, the pin being engaged with an abutment member of one of said coupling segments, and the bridge having a bolt threaded therethrough and which is engaged with an abutment member of the other of said coupling segments.
 14. The pipe coupling of claim 1, in which each end of each said coupling segment is provided with said inclined juxtaposed end faces, at least one of said securing means comprising spaced inter-fitting lugs oriented in planes perpendicular to said end faces, and which are connected to each other by a traction bolt having its longitudinal axis extending parallel to the plane of said end faces.
 15. The pipe coupling of claim 14, in which each end of each said coupling segment is provided with said inclined lugs.
 16. The pipe coupling of claim 15, in which said lugs provide positioning and reaction members for a removable traction means usable in closing the coupling and aligning the bores in the respective lugs to permit insertion of said traction bolt.
 17. The pipe coupling of claim 7, in which said securing means include abutment members on adjacent coupling segments, and a traction member interconnecting said abutment members for closing and coupling, said traction member being comprised by a yoke having spaced parallel links interconnected by a transverse pin at one of their ends and interconnected by a bridge at the other of their ends, the pin being engaged with an abutment member of one of said coupling segments, and the bridge having a bolt threaded therethrough and which is engaged with an abutment member of the other of said coupling segments.
 18. The pipe coupling of claim 7, in which each end of each said coupling segment is provided with said inclined juxtaposed end faces, at least one of said securing means comprising spaced inter-fitting lugs oriented in planes perpendicular to said end faces, and which are connected to each other by a traction bolt having its longitudinal axis extending parallel to the plane of said end faces.
 19. The pipe coupling of claim 18, in which each end of each coupling segment is provided with said inclined lugs.
 20. The pipe coupling of claim 19, in which said lugs provide positioning and reaction members for a removable traction means usable in closing the coupling and aligning the bores in the respective lugs to permit insertion of said traction bolt.
 21. The pipe coupling of claim 1 in which said traction means are bolts engaged with radially extending bolting pads at the respective ends of the coupling segments. 